• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.10
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• pp.814-819
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• 2010

Porous carbon electrodes with wooden materials are manufactured by molding carbonized wood powder. Electrical properties of the interface for electrolyte and porous carbon electrode are investigated from viewpoint of NaCl electrolyte concentration, capacitance and complex impedance. Density of porous carbon materials is 0.47~0.61 g/$cm^3$. NaCl electrolytic absorptance of the porous carbon materials is 5~30%. As the electrolyte concentration increased, capacitance is increased and electric resistance is decrease with electric double layer effect of the interface. The electric current of the porous carbon electrode compared in the copper and the high density carbon electrode was improved on a large scale, due to a increase in surface area. The circuit current increased as the distance between of the porous carbon electrode and the zinc electrode decreased, due to increase in electric field. Experimental results indicated that the current properties of galvanic cell could be improved by using porous carbon electrode.

• Journal of Electrochemical Science and Technology
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• v.8 no.3
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• pp.236-243
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• 2017

A fixed-bed zinc/nickel redox flow battery (RFB) is designed and developed. The proposed cell has been established in the form of a fixed bed RFB. The zinc electrode is immersed in an aqueous NaOH solution (anolyte solution) and the nickel electrode is immersed in the catholyte solution which is a mixture of potassium ferrocyanide, potassium ferricyanide and sodium hydroxide as the supporting electrolyte. In the present work, the electrode area has been maximized to $1500cm^2$ to enforce an increase in the energy efficiency up to 77.02% at a current density $0.06mA/cm^2$ using a flow rate $35cm^3/s$, a concentration of the anolyte solution is $1.5mol\;L^{-1}$ NaOH and the catholyte solution is $1.5mol\;L^{-1}$ NaOH as a supporting electrolyte mixed with $0.2mol\;L^{-1}$ equimolar of potassium ferrocyanide and potassium ferricyanide. The outlined results from this study are described on the basis of battery performance with respect to the current density, velocity in different electrolytes conditions, energy efficiency, voltage efficiency and power of the battery.

• International Journal of Korean Welding Society
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• v.2 no.1
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• pp.1-10
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• 2002

The thermal contact conductance at different temperatures and with different electrode forces and zinc coating morphology was measured by monitoring the infrared emissions from the one dimensionally simulated contact heat transfer experiments. The contact heat transfer coefficients were presented as a function of the harmonic mean temperature of the two contacting surfaces. Using these contact heat transfer coefficients and experimentally measured temperature profiles, the electrical contact resistivities both for the faying interface and electrode-workpiece interface were deduced from the numerical analyses of the one dimension simulation welding. It was found that the average value of the contact heat transfer coefficients for the material with zinc coating (coating weight from 0 g/$mm^2$to 100 g/$mm^2$) ranges from 0.05 W/$mm^2$$^{\circ}C$ to 2.0 W/$mm^2$$^{\circ}C$ in the temperature range above 5$0^{\circ}C$ harmonic mean temperature of the two contacting surfaces. The electrical contact resistivity deduced from the one dimension simulation welding and numerical analyses showed that the ratio of electrical contact resistivity at the laying interface to the electrical contact resistivity at the electrode interface is smaller than one far both bare steel and zinc coated steel.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.310-315
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• 1997

An extensive corrosion study was initiated by galvalume steel sheet manufacturing company to clarify the corrosion behavior of zinc and zinc and zinc-alloy coated automotive sheet steel in out panel and electrical application. Since the early 1980's the use of zinc and aluminum alloy coated steel for vehicular corrosion protection has increased drastically. This paper describes the evaluation of formability, weldability and painted corrosion performance of galvalume steel sheet. This paper presents an overview of the program and some initial test results on the weldability, lifetime of the electrode tip shape of the spot welding and corrosion protection. Galvalume steel sheet improved corrosion performance and spot weldability of galvalume steel has no problem for the variation of welding current. And tip lifetime was changed according to the influence of shape.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.118-121
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• 2003

The electrochemical behaviors of UBM nickel were investigated. Electrode potential has been changed with the surface composition. Zinc is dissolved into the solution immediately after immersion. Electrode potential has three distinct regions: Zinc dissolution region, transient region and nickel plating region. The effects additives on electrode potential and polarization curves were also investigated. The addition of suppressor lowered the current density which is related with deposition rate.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.7
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• pp.1259-1264
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• 2010

This paper was researched about effectiveness of the electrochemical cell which is composed of the sea water and the Cu/Zn electrode. The electric potential difference between copper and zinc finally reached 0.51 volts. Short current decreased with time. It might depend on the electromotive force decreasing. Confirmed the load resistance and electrode affect in electromotive force and electric current. The resistance which shows a maximum output power was 20[$\Omega$], and the maximum output power from this resistance was evaluated as 0.736mW. In order to calculate the energy which creates from electrochemical cell, charging voltage of the capacitor with various capacitance was investigated. It was found that energy harvesting possibility of the cell which is made of a sea water electrolyte and the copper/the zinc.

• Transactions on Electrical and Electronic Materials
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• v.16 no.3
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• pp.135-138
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• 2015

A manganese dioxide (MnO₂) layer and zinc (Zn) layer are used as the cathode and the anode to develop filmtype manganese battery, in which a stack of a MnO₂ layer, gel electrolyte, and Zn layer are sandwiched between two plastic layers. This paper describes the chemical equation of swelling control upon the film-type manganese battery. We examined the reduction of hydrogen formation, by using calcium hydroxide Ca(OH)₂ as an additive in the electrolyte of film-type manganese battery. The phenomena or an effect of reduced hydrogen gas was proven by cyclic voltammogram, X-ray photoelectron spectra (XPS), and volume of hydrogen formation. The amount of H₂ gas generation in the presence of Ca²⁺ ion was reduced from 4.81 to 4.15 cc/g-zinc (14%), and the corrosion of zinc electrode in the electrolyte was strongly inhibited as time passed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.6
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• pp.401-405
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• 2017

Because silicon thin film solar cells have a high absorption coefficient in visible light, they can absorb 90% of the solar spectrum in a $1-{\mu}m$-thick layer. Silicon thin film solar cells also have high transparency and are lightweight. Therefore, they can be used for building integrated photovoltaic (BIPV) systems. However, the contact electrode needs to be replaced for fabricating silicon thin film solar cells in BIPV systems, because most of the silicon thin film solar cells use metal electrodes that have a high reflectivity and low transmittance. In this study, we replace the conventional aluminum top electrode with a transparent aluminum-doped zinc oxide (AZO) electrode, the band level of which matches well with that of the intrinsic layer of the silicon thin film solar cell and has high transmittance. We show that the AZO effectively replaces the top metal electrode and the bottom fluorine-doped tin oxide (FTO) substrate without a noticeable degradation of the photovoltaic characteristics.

• Korean Journal of Materials Research
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• v.29 no.8
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• pp.505-510
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• 2019

Zn-ion supercapacitors (ZICs) show high energy densities with long cycling life for use in electronic devices. Porous Zn electrodes as anodes for ZICs are fabricated by chemical etching process using optimized conditions. The structures, morphologies, chemical bonding states, porous structure, and electrochemical behavior are examined. The optimized porous Zn electrode shows a root mean square of roughness of 173 nm and high surface area of $153{\mu}m^2$. As a result, ZIC using the optimized porous Zn electrode presents excellent electrochemical performance with high specific capacitance of $399F\;g^{-1}$ at current density of $0.5A\;g^{-1}$, high-rate performance ($79F\;g^{-1}$ at a current density of $10.0A\;g^{-1}$), and outstanding cycling stability (99 % after 1,500 cycles). The development of energy storage performance using synergistic effects of high roughness and high surface area is due to increased electroactive sites by surface functionalization of Zn electrode. Thus, our strategy will lead to a rational design and contribute to next-generation supercapacitors in the near future.

• Korean Journal of Materials Research
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• v.20 no.8
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• pp.401-407
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• 2010

We studied the influence of different types of metal electrodes on the performance of solution-processed zinc tin oxide (ZTO) thin-film transistors. The ZTO thin-film was obtained by spin-coating the sol-gel solution made from zinc acetate and tin acetate dissolved in 2-methoxyethanol. Various metals, Al, Au, Ag and Cu, were used to make contacts with the solution-deposited ZTO layers by selective deposition through a metal shadow mask. Contact resistance between the metal electrode and the semiconductor was obtained by a transmission line method (TLM). The device based on an Al electrode exhibited superior performance as compared to those based on other metals. Kelvin probe force microscopy (KPFM) allowed us to measure the work function of the oxide semiconductor to understand the variation of the device performance as a function of the types metal electrode. The solution-processed ZTO contained nanopores that resulted from the burnout of the organic species during the annealing. This different surface structure associated with the solution-processed ZTO gave a rise to a different work function value as compared to the vacuum-deposited counterpart. More oxygen could be adsorbed on the nanoporous solution-processed ZTO with large accessible surface areas, which increased its work function. This observation explained why the solution-processed ZTO makes an ohmic contact with the Al electrode.